The San Francisco Ballet will have a tall order to fill if Muriel Maffre retires next year, and not just because the majestic principal dancer is 5 feet 10 inches. Elegant, intelligent and impossibly long-limbed, this chic Frenchwoman is only one among a clutch of international-caliber stars who have launched the company into ballet's big leagues, but she is irreplaceable.

She joined the company in 1990, just as Artistic Director Helgi Tomasson was refashioning the troupe from a well-regarded regional player to a top-tier powerhouse. Her physical assets are obvious: lines that seem to stretch to infinity, jaw-dropping leg extension, beautifully bowed feet. But it is her thoughtful artistry that makes Maffre one of San Francisco Ballet's most beloved ballerinas.

She can be sexy and sharp in William Forsythe's "In the Middle, Somewhat Elevated," and all softness and beneficence as "Sleeping Beauty's" Lilac Fairy. Her Myrtha, queen of the ghostly maidens of "Giselle," is both chilling and eloquent; her "Choleric" in George Balanchine's "Four Temperaments" is one of clarity and command. In recent seasons she's delivered pathos as Medea in Yuri Possokhov's "Damned" and punch lines as a moribund swan in Alexei Ratmansky's "Les Carnaval des Animaux."

But just when you think you have Maffre figured out, she pushes her range further. At the company's 2002 gala, she danced the real "Dying Swan," rescuing Anna Pavlova's iconic solo from decades of parody with her shuddering arms.

That same year, Maffre danced the world premiere of Christopher Wheeldon's "Continuum" with then-San Francisco Ballet principal Benjamin Pierce, now her boyfriend. Pierce, a video artist, hopes to film Maffre's "Dying Swan" while she is in her dancing prime.

San Francisco Ballet's engagement at Les étés de la danse de Paris will be a homecoming for Maffre. She grew up in a town just west of the city and trained at the Paris Opera Ballet School. Now nearing 40, she has said that the company's next San Francisco season may be her last. Dance lovers are fortunate to catch her now.